Shares in the vaunted 185-year-old bond shop tumbled 45 percent to close at $7.79 a share on news that a deal to raise much-needed cash from the Korean Development Bank once again stalled, triggering fears that Lehman was about to follow the path of the now-defunct Bear Stearns.

Lehman’s problems have been a closely watched situation because the investment bank holds some $40 billion in mortgage inventory on its balance sheet, which the bank has been desperately trying to unload over the past few months.

Fuld and newly appointed President Bart McDade also have been trying to raise capital from foreign and domestic parties to quiet the growing questions over Lehman’s capital levels.

Lehman hopes to shed light on its next moves when it pre-announces its earnings this morning a full week ahead of its scheduled release, according to a statement issued by the investment bank late yesterday.

So far, the lack of a definitive announcement from the bank has raised concerns that Fuld, a characteristically tough negotiator, is driving too hard of a bargain to restore Lehman, even as he’s seen by prospective buyers as being in dire straits.

Fuld’s hard-nosed dealmaking tactics may have originally sent KDB officials flying back to South Korea about a month ago without striking a deal.

“He’s playing poker with the market and everyone knows his hand,” said one banker of the situation.

To be sure, Fuld’s task is a tall order: Sell assets that no one wants to buy at a fair price and raise enough capital from private-equity firms seeking the sweetest deal.

Meanwhile, Fuld’s no-nonsense tactics have pitted him against top brass of asset management unit Neuberger Berman, which has been placed on the chopping block.

Neuberger execs have been fighting for a spin-off because their fortunes are tied to Lehman’s success and days like yesterday underscore the disparity between Neuberger’s solid performance and Lehman’s uncertain future.

Expectations were that Lehman would take the next phase of bids from private-equity investors, including Bain Capital, Kohlberg Kravis Roberts, TPG and Hellman & Friedman in two days.

Sources tell The Post that the anxiety levels on Wall Street also extend internally as even senior bankers at Lehman express grave concerns about the outlook for the bank and grouse that Fuld has not settled on a definitive solution, thus allowing rumors to run rampant.

Indeed, it has been tough to sort out fact from fiction, as numerous reports hint that Lehman is a takeover target from banks such as HSBC, Royal Bank of Scotland, Bank of America, Barclays, BNP Paribas and Société Générale.

Although it’s unclear if any buyout is likely, sources told The Post that Lehman has three separate teams hammering out deals to sell its asset management unit, raise capital and seek an outright buyer for the firm.

“This is a multi-headed monster and we don’t know what triggers they are going to pull,” said a source close to one of the bidders.